<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
  <style>
    .box {
      text-align: center;
    }
    .box a {
      display: inline-block;
      width: 36px;
      height: 36px;
      --width: 36px;
      background-color: #f7f7f7;
      border: 1px solid #ccc;
      text-align: center;
      line-height: var(--width);
      text-decoration: none;
      color: #333333;
    }
  </style>
</head>
<body>
  <div class="box">
    <a href="#">1</a>
    <a href="#">2</a>
    <a href="#">3</a>
    <a href="#">4</a>
    <a href="#">5</a>
    <a href="#">6</a>
    <a href="#">7</a>
  </div>
</body>
</html>